A Trump administration official said Thursday that the Pentagon will send almost 4,000 more American forces to Afghanistan.

The official hoped a stalemate in a war that has now passed to a third U.S. commander in chief to be broken.

The bulk of the new troops will train and advise Afghan forces, according to the administration official, who wasn’t authorized to discuss details of the decision publicly and spoke on condition of anonymity. A smaller number would be assigned to counterterror operations against the Taliban and the Islamic State, the official said.

The decision by Defense Secretary James Mattis could be announced as early as next week, the official said. It follows President Donald Trump’s move to give Mattis the authority to set troop levels and seeks to address assertions by the top U.S. commander in Afghanistan that he doesn’t have enough forces to help Afghanistan’s army against a resurgent Taliban insurgency.

The spokesman for Afghanistan’s defense ministry said the Afghan government supports the U.S. decision to send more troops.

“The United States knows we are in the fight against terrorism, ” he said. “We want to finish this war in Afghanistan with the help of the NATO alliance.”

Trump, who has delegated authority for U.S. troop numbers in Afghanistan, has inherited America’s longest conflict with no clear endpoint or a defined strategy for U.S. success, though U.S. troop levels are far lower than they were under Presidents Barack Obama and George W. Bush.

In 2009, Obama authorized a surge of 30,000 troops into Afghanistan, bringing the total there to more than 100,000 before drawing down over the rest of his presidency.

Trump has barely spoken about Afghanistan as a candidate or president.